Advice on connecting an air conditioner

[Howard]

I don't know which supplier my installer used, but the advert below shows the multi unit which was installed. So it's one inverter attached to two wall units. He emphasised that it is worth paying a little extra for the Premier wall units, as shown. They apparently look better than the basic units.

I've shown the advert, because it goes some way to addressing your initial request of breaking down the cost of the units and fitting. I would guess you would have to add £300 - £500 to the basic cost of £1,113 to include the full kit which was used for the installation. For example, chatting to the installer on day two, the cost of just the extra plastic ducting elbow which was fitted later was £18 and that was the reason they didn't carry it on their van. The ducting they used was very neat and, I guess wasn't cheap.

https://www.saturnsales.co.uk/Mitsubish ... 7KEALw_wcB

Brilliant - thanks very much Howard.

I'm sure I won't be the only one interested in an interim report later in the summer...

Cheers,

Itsallaguess

Bliss!

Howard

[Itsallaguess]

I'm sure I won't be the only one interested in an interim report later in the summer...

Bliss!

Great news - and nice to hear that someone's comfortable in all this heat!

Cheers,

Itsallaguess

[Howard]

I'm sure I won't be the only one interested in an interim report later in the summer...

Bliss!

Great news - and nice to hear that someone's comfortable in all this heat!

Cheers,

Itsallaguess

Hopefully this is a little more helpful feedback on the aircon fitted a few weeks ago.

I’m very pleased with the outcome.

I sold my portable air conditioner in the hot spell just over a week ago. It was priced competitively on Gumtree and the first response came in within 15 minutes, from someone who came and collected that day. It was a very useful research project which ended up costing a bit less than £200 but persuaded me that having the compressor and fan in one unit was just too noisy.

In contrast, the split installation is dramatically more powerful in cooling and amazingly quiet, even on its most powerful setting. We have had one or two very hot days and last Saturday came home to a very hot house with all the windows closed after a day out. The house is well insulated and the interior was around 29 deg C and humid. With no wind outside, natural cooling is very slow..

In that situation, setting the aircon to around 25 deg on a low fan setting had an immediate effect. Within five minutes the (medium sized) room felt refreshingly cool. The aircon reduced the high humidity as well. Briefly standing in its air flow was very refreshing.

So the system doesn’t need to be set to 20 deg. About 23 deg on a hot evening is ideal. Looking at a separate room thermometer, the temp varies between 22 - 24 and the external inverter cycles so that it is cooling the refrigerant only occasionally. The internal fan runs continuously and gently circulates the air in the room. I had a look at my electricity meter, and in these conditions the power used is not that high.

So because of its effectiveness, when the bedroom is very hot the aircon has to be switched on for only a few minutes before going to bed. By the time it takes to clean teeth etc the room feels cool and only once have I set it on the timer to turn off after an hour. Once the room is cool, the insulation works in our favour and it stays that way for some time after the unit is switched off.

One could say that it has been an expensive investment so far as it has probably only been switched on for around 20 hours. However it has improved my quality of life. I hate going to bed in a hot bedroom and can’t sleep in the heat. And on a hot evening downstairs we can close the window to stop insects coming in and watch TV in comfort. Now at the press of a remote control I can improve my environment and relax. And the total running cost of those 20 hours was about £3 at 16p per kWh.

So I’m very pleased with the installation and can’t see any downsides.

Regards

Howard

[Itsallaguess]

So I’m very pleased with the installation and can’t see any downsides.

Thanks for coming back with an updated review Howard - it sounds like you're very happy things, which is great news.

Can I ask if you've tried them in heating-mode yet?

I was just wondering if there's any of the traditional 'heat smell' that you often get with electrical heating, or is that completely absent with these inverter-units?

Also, did you get the 2Kw versions of the wall units, or the higher-rated 2.5Kw units?

Am I correct in thinking that the inverter you've had installed is the SCM40ZS-S that can do two wall units only? If so, were you tempted to go for one of the higher-rated inverters at all, to perhaps give some further options at any point?

Cheers,

Itsallaguess

[Howard]

So I’m very pleased with the installation and can’t see any downsides.

Thanks for coming back with an updated review Howard - it sounds like you're very happy things, which is great news.

Can I ask if you've tried them in heating-mode yet?

I was just wondering if there's any of the traditional 'heat smell' that you often get with electrical heating, or is that completely absent with these inverter-units?

Also, did you get the 2Kw versions of the wall units, or the higher-rated 2.5Kw units?

Am I correct in thinking that the inverter you've had installed is the SCM40ZS-S that can do two wall units only? If so, were you tempted to go for one of the higher-rated inverters at all, to perhaps give some further options at any point?

Cheers,

Itsallaguess

Yes, ironically, I used the aircon in heating mode quite a bit in the chilly evenings after installation. It was quiet, no hot smell and a gentle warming which quickly brought the room temperature up. I would say it was more comfortable than using a convection heater. But it was only used briefly for a few evenings where I didn't use the gas central heating to warm the whole house. I doubt if there will be a "heat smell" next winter because the units have comprehensive air filters which stop any dust getting on hot surfaces.

My wall units are 2 Kw rated and, yes the inverter is the SCM40ZS-S. I wasn't tempted to go for a higher power external unit because our larger sitting room is on the North side of the house and is cool even on hot days and anyway would need a very long run of piping to reach it. The (cooled) family room we watch TV in is next to the kitchen, it is smaller and is on the warm side of the house. The two wall units are so powerful in operation that, if I left the doors open, I'm sure they would cool the kitchen and the landing and adjacent bedrooms.

As a keen gardener, I was particularly concerned not to introduce an "industrial" feel to my garden so am pleased with the relatively small size of the external unit. This is now camouflaged in a tastefully designed diy frame which serves as a side table for my bbq. This has worked as no visitor has yet spotted the unit.

Your question regarding the 2.5 kW wall units has given me an opportunity to be pretentious . Mrs H and I were invited to a reception at the House of Lords the other day on the terrace next to the Thames. I noticed that the aircon wall units were Mitsubishi, exactly the same as mine, but probably the 2.5kW versions as they were cooling a much bigger space. Whether that confirms my choice was correct or not I will leave to you to decide!

regards

Howard

[Itsallaguess]

My wall units are 2 Kw rated and, yes the inverter is the SCM40ZS-S.

I wasn't tempted to go for a higher power external unit because our larger sitting room is on the North side of the house and is cool even on hot days and anyway would need a very long run of piping to reach it. The (cooled) family room we watch TV in is next to the kitchen, it is smaller and is on the warm side of the house.

The two wall units are so powerful in operation that, if I left the doors open, I'm sure they would cool the kitchen and the landing and adjacent bedrooms.

That's great information to know, thanks Howard.

With a limited number of wall-units for the inverter, it's good to know that judicious siting of the wall-units, especially if used in a more 'open-plan' position, can adequately cool quite large areas.

What a great, interesting thread this has turned out to be.

Cheers,

Itsallaguess

[todthedog]

We have had ashp air/air, in Brittany, again in Sweden (everyone has them) and have recently installed a unit in our kitchen/lounge in Wales.
Mitsubishi units in all three locations. Our recent costs £700 for unit £500 for the install refrigeration engineer, £100 for electrician to run a dedicated line and circuit breakers etc.
Happily cools 35m2 kitchen/lounge. I have no concerns that it will heat the same area in Autumn and Spring.
Easy and convenient highly recommend, just make sure your unit is correctly sized for the area.

[Howard]

My wall units are 2 Kw rated and, yes the inverter is the SCM40ZS-S.

I wasn't tempted to go for a higher power external unit because our larger sitting room is on the North side of the house and is cool even on hot days and anyway would need a very long run of piping to reach it. The (cooled) family room we watch TV in is next to the kitchen, it is smaller and is on the warm side of the house.

The two wall units are so powerful in operation that, if I left the doors open, I'm sure they would cool the kitchen and the landing and adjacent bedrooms.

That's great information to know, thanks Howard.

With a limited number of wall-units for the inverter, it's good to know that judicious siting of the wall-units, especially if used in a more 'open-plan' position, can adequately cool quite large areas.

What a great, interesting thread this has turned out to be.

Cheers,

Itsallaguess

At risk of being a bit of a Nerd, given the weather forecast, I thought it might be interesting to record how much electricity the aircon used yesterday.

Both units were used. The bedroom throughout the night and the family room unit for the rest of the day. As recorded in earlier posts, we don't set the temperature very low. The units were ticking over and reducing what would have been an internal level of close to 30 degrees to around 23-24 degrees which felt very cool/almost chilly compared with the temperature outside which reached at least 30.

There were four of us in the house most of the day and family visitors who came and enjoyed the cool. Much leaving doors open letting the cool escape etc!

I read the meter yesterday morning and 24 hours later today. The total amount of electricity we consumed was 15 kWh. And on a normal summer day I'd expect to use around 5-8 kWh as Mrs H was cooking by electricity and despite the heat we had some cooked meals and snacks.

So I reckon the aircon used 10kWh, at a cost of 15.53p per kWh, so around £1.50. I was very pleasantly surprised at how low this was as this was the absolute maximum usage anticipated.

The major benefit has been blissful sleep at night. Usually just cooling the bedroom for 15 minutes before sleeping and perhaps in the early morning.

So surprisingly low running costs.

regards

Howard

[Itsallaguess]

There were four of us in the house most of the day and family visitors who came and enjoyed the cool. Much leaving doors open letting the cool escape etc!

I read the meter yesterday morning and 24 hours later today. The total amount of electricity we consumed was 15 kWh. And on a normal summer day I'd expect to use around 5-8 kWh as Mrs H was cooking by electricity and despite the heat we had some cooked meals and snacks.

So I reckon the aircon used 10kWh, at a cost of 15.53p per kWh, so around £1.50. I was very pleasantly surprised at how low this was as this was the absolute maximum usage anticipated.

The major benefit has been blissful sleep at night. Usually just cooling the bedroom for 15 minutes before sleeping and perhaps in the early morning.

So surprisingly low running costs.

Very interesting data Howard - thanks for taking note of this type of stuff, as it's certainly something that I'm keen to appreciate, and I'm sure others too.

After the sort of hot and stuffy week that we've had, of course, I will assume that at least some of those running costs may have been mitigated by the price of admission for your family visitors!

:O)

Cheers,

Itsallaguess

[AF62]

To resurrect an old thread, after this last warm summer and inspired by this thread back in 2019 I finally resolved to get air conditioning fitted.

I was interested in the type of multi-split system which was originally mentioned (one outside unit serving two or more inside units) to have one upstairs in the bedroom and one downstairs in the living / dining room. The living / dining room faces west has a large window area so it can get really unpleasantly warm in the summer. Although the bedroom faces east and gets less direct sun, it still warms up significantly. To cool the bedroom, a few years ago I had bought a 'push around' unit where you stick the hose through the window, and it was 'ok' but it was far too noisy to sleep with it running or even watch TV when it was on.

Interestingly when I made enquiries about a multi-split system with several different installers, each of them without prompting suggested installing separate units instead as the installed cost would be significantly cheaper than a multi-split option - although there is the downside of needing to find space for two outside units.

For the units I have had installed - a 5Kw unit downstairs and a 3.5Kw upstairs, the total cost of separate units installed was £2,600 inc VAT but the cost of a multi-split with the same inside units would have been £3,400 inc VAT. If I had chosen lower power units, reducing them to a 3.5Kw and 2.5Kw then the cost of the multi-split would have come closer to the same price as the separate 5Kw and 3.5Kw units, but as I had space for two units outside and I wanted the units to be powerful enough to cool adjoining rooms upstairs and down, I went with the higher powered separate unit option.

The installation took place last week (three guys, one day) so I have only tried them in the heating mode so far. They are the same Mitsubishi Heavy Industries SRK-ZS models mentioned earlier in the thread and they do seem very quiet at their lowest setting but actually not bad at the highest - certainly far far quieter than the old 'push around' unit. The lowest setting is quieter than the birds 'cheeping' in the summer with the windows open and I cannot foresee any likelihood of having sleep disturbed whatever the fan setting.

I was concerned that the outside units (SRC-ZS models) might disturb the neighbours when they are in use, but they are also impressively quiet even when the inside units are running at full power.

I had looked at the optional extra WiFi controls (I have a Hive thermostat and a houseful of smart bulbs and other Google Home smart devices) but considered that the combination of the powerful / rapid cooling and the weekly programming settings you can input then it was likely not needed. And if I changed my mind I could always get them installed at a later date.

Roll on summer 2021!

[Howard]

To resurrect an old thread, after this last warm summer and inspired by this thread back in 2019 I finally resolved to get air conditioning fitted.

Roll on summer 2021!

Well done! I don't think you will regret your decision.

I looked at our energy consumption for 2020 a couple of days ago as I had to send in a meter reading and the usage and overall cost for the year looks as though it will be the lowest for years. We have saved gas in the Autumn as the aircon was used to take the chill off our family room rather than firing up the central heating. Maybe another reason is that the weather has been milder and lockdown has meant zero visitors inside, but the running cost of the system continues to be small. Hope this is the same for you.

Thanks for the update.

regards

Howard

[AF62]

To resurrect an old thread, after this last warm summer and inspired by this thread back in 2019 I finally resolved to get air conditioning fitted.

Roll on summer 2021!

Well done! I don't think you will regret your decision.

And I am not, after we have had the first two (of hopefully many) warm days this year.

I looked at our energy consumption for 2020 a couple of days ago as I had to send in a meter reading and the usage and overall cost for the year looks as though it will be the lowest for years. We have saved gas in the Autumn as the aircon was used to take the chill off our family room rather than firing up the central heating. Maybe another reason is that the weather has been milder and lockdown has meant zero visitors inside, but the running cost of the system continues to be small. Hope this is the same for you.

Looking at the energy consumption figures from the smart meter it seems to use very little electricity overall - a fairly hefty consumption of 1kW for the downstairs 5kW unit whilst it is pulling the temperature down, but that was quite quick in reducing the 25c temperature to 21c in 20 minutes today whilst the sun was blasting through the windows, and then very little consumption as it ticks over keeping it at that level.

For the upstairs unit dealing with the bedroom, it is handy that I changed to Octopus Go Faster recently so only pay 5.5p / kWh from 20:30 to 01:30 which will cover most of the time that unit is on.

Mind you I am glad that I got the main fuse to the house upgraded to 100amps when I got an EV. Timing everything to start at 20.30, then with the car charging, the dishwasher and washing machine running, and two aircon units just started, the smart meter 'in-home' display needle is banging against the end of the display for kWh consumption.

[Howard]

To resurrect an old thread, after this last warm summer and inspired by this thread back in 2019 I finally resolved to get air conditioning fitted.

Roll on summer 2021!

Well done! I don't think you will regret your decision.

And I am not, after we have had the first two (of hopefully many) warm days this year.

I looked at our energy consumption for 2020 a couple of days ago as I had to send in a meter reading and the usage and overall cost for the year looks as though it will be the lowest for years. We have saved gas in the Autumn as the aircon was used to take the chill off our family room rather than firing up the central heating. Maybe another reason is that the weather has been milder and lockdown has meant zero visitors inside, but the running cost of the system continues to be small. Hope this is the same for you.

Looking at the energy consumption figures from the smart meter it seems to use very little electricity overall - a fairly hefty consumption of 1kW for the downstairs 5kW unit whilst it is pulling the temperature down, but that was quite quick in reducing the 25c temperature to 21c in 20 minutes today whilst the sun was blasting through the windows, and then very little consumption as it ticks over keeping it at that level.

For the upstairs unit dealing with the bedroom, it is handy that I changed to Octopus Go Faster recently so only pay 5.5p / kWh from 20:30 to 01:30 which will cover most of the time that unit is on.

Mind you I am glad that I got the main fuse to the house upgraded to 100amps when I got an EV. Timing everything to start at 20.30, then with the car charging, the dishwasher and washing machine running, and two aircon units just started, the smart meter 'in-home' display needle is banging against the end of the display for kWh consumption.

Glad you are pleased with the aircon. We started using ours in the last two days. And it was useful as an occasional top up heater in the winter.

Like you we now have a BEV and I'm expecting Octopus to fit a smart meter this week so we can convert to the cheaper tariff. Your helpful comment about the fuse made me check ours! It's 100 amp.

regards

Howard

[AF62]

I'm expecting Octopus to fit a smart meter this week so we can convert to the cheaper tariff.

In case you were not aware, as well as the advertised Octopus Go tariff aimed at EV owners giving 4 hours at 5p/kWh between 00:30 and 04:30, there is also the experimental Octopus Go Faster tariff which gives 3, 4, or 5 hours of cheap electric costing 4.5, 5, or 5.5p/kWh and you get to pick the hours with earliest period starting at 20:30 and the latest ending at 06:30. To get onto Go Faster you have to email them and ask.

[Howard]

I'm expecting Octopus to fit a smart meter this week so we can convert to the cheaper tariff.

In case you were not aware, as well as the advertised Octopus Go tariff aimed at EV owners giving 4 hours at 5p/kWh between 00:30 and 04:30, there is also the experimental Octopus Go Faster tariff which gives 3, 4, or 5 hours of cheap electric costing 4.5, 5, or 5.5p/kWh and you get to pick the hours with earliest period starting at 20:30 and the latest ending at 06:30. To get onto Go Faster you have to email them and ask.

Many thanks, I will email them after the smart meter installation.

We are on the edge of mobile signal coverage and some neighbours report that their smart meters don't communicate. It seems to me that 100 metres difference in location can be critical. Next door have an Octopus smart meter (but no BEV) and have to email monthly readings. So I'm not sure about connectivity. If it is patchy, I will check if it is possible to transfer to Go or Go Faster and submit readings manually.

regards

Howard